Thema: Delphi Jpeg komprimieren

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Benutzerbild von netscanner
netscanner

Registriert seit: 2. Dez 2005
Ort: Dieburg
280 Beiträge
 
Delphi 6 Enterprise
 
#1

Jpeg komprimieren

  Alt 7. Jul 2006, 12:39
Hallo,
ich habe für eine JPEG Bildkomprimierung den Delphi Beispiel Code genommen...

Er macht auch alles wunderbar...Nur das Problem ist ich wollte das neue Bild was in TImage angezeigt wird speichern.
Mit:
image1.picture.savetofile('xyz.jpeg'); Wenn ich diesen schritt aber ausführe speichert er mir das alte (nicht komprimierte) bild....
Was mach ich falsch?


Delphi-Quellcode:
unit jpegdemo;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, jpeg, ExtCtrls, FileCtrl, ComCtrls, Menus, printers;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    DirectoryListBox1: TDirectoryListBox;
    FileListBox1: TFileListBox;
    Panel3: TPanel;
    DriveComboBox1: TDriveComboBox;
    Scale: TComboBox;
    PixelFormat: TComboBox;
    ColorSpace: TComboBox;
    Performance: TComboBox;
    ProgressiveDisplay: TCheckBox;
    IncrementalDisplay: TCheckBox;
    MainMenu1: TMainMenu;
    File1: TMenuItem;
    Open1: TMenuItem;
    N1: TMenuItem;
    Print1: TMenuItem;
    PrinterSetup1: TMenuItem;
    N2: TMenuItem;
    Exit1: TMenuItem;
    OpenDialog1: TOpenDialog;
    PrinterSetupDialog1: TPrinterSetupDialog;
    PrintDialog1: TPrintDialog;
    ScrollBox1: TScrollBox;
    Image1: TImage;
    procedure FileListBox1DblClick(Sender: TObject);
    procedure SetJPEGOptions(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure ProgressUpdate(Sender: TObject; Stage: TProgressStage;
      PercentDone: Byte; RedrawNow: Boolean; const R: TRect; const Msg: string);
    procedure Open1Click(Sender: TObject);
    procedure Print1Click(Sender: TObject);
    procedure PrinterSetup1Click(Sender: TObject);
    procedure Exit1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    procedure OpenFile(const Filename: string);
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.OpenFile(const Filename: string);
begin
  try
    Image1.Picture.LoadFromFile(Filename);
  except
    on EInvalidGraphic do
      Image1.Picture.Graphic := nil;
  end;
  SetJPEGOptions(self);
end;

procedure TForm1.FileListBox1DblClick(Sender: TObject);
begin
  OpenFile(FileListbox1.Filename);
end;

procedure TForm1.SetJPEGOptions(Sender: TObject);
var
  Temp: Boolean;
begin
  Temp := Image1.Picture.Graphic is TJPEGImage;
  if Temp then
    with TJPEGImage(Image1.Picture.Graphic) do
    begin
      PixelFormat := TJPEGPixelFormat(Self.PixelFormat.ItemIndex);
      Scale := TJPEGScale(Self.Scale.ItemIndex);
      Grayscale := Boolean(Colorspace.ItemIndex);
      Performance := TJPEGPerformance(Self.Performance.ItemIndex);
      ProgressiveDisplay := Self.ProgressiveDisplay.Checked;
    end;
  Scale.Enabled := Temp;
  PixelFormat.Enabled := Temp;
  Colorspace.Enabled := Temp;
  Performance.Enabled := Temp;
  ProgressiveDisplay.Enabled := Temp
    and TJPEGImage(Image1.Picture.Graphic).ProgressiveEncoding;
  Image1.IncrementalDisplay := IncrementalDisplay.Checked;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Scale.ItemIndex := 0;
  PixelFormat.ItemIndex := 0;
  Colorspace.ItemIndex := 0;
  Performance.ItemIndex := 0;
  OpenDialog1.Filter := GraphicFilter(TGraphic);
  FileListbox1.Mask := GraphicFileMask(TGraphic);
  Image1.OnProgress := ProgressUpdate;
end;

procedure TForm1.ProgressUpdate(Sender: TObject; Stage: TProgressStage;
  PercentDone: Byte; RedrawNow: Boolean; const R: TRect; const Msg: string);
begin
  if Stage = psRunning then
    Caption := Format('%d%%',[PercentDone])
  else
    Caption := 'Form1';
end;


procedure TForm1.Open1Click(Sender: TObject);
begin
  if OpenDialog1.Execute then
    OpenFile(OpenDialog1.FileName);
end;

procedure TForm1.Print1Click(Sender: TObject);
var
  AspectRatio: Single;
  OutputWidth, OutputHeight: Single;
begin
  if not PrintDialog1.Execute then Exit;
  Printer.BeginDoc;
  try
    OutputWidth := Image1.Picture.Width;
    OutputHeight := Image1.Picture.Height;
    AspectRatio := OutputWidth / OutputHeight;
    if (OutputWidth < Printer.PageWidth) and
      (OutputHeight < Printer.PageHeight) then
    begin
      if OutputWidth < OutputHeight then
      begin
        OutputHeight := Printer.PageHeight;
        OutputWidth := OutputHeight * AspectRatio;
      end
      else
      begin
        OutputWidth := Printer.PageWidth;
        OutputHeight := OutputWidth / AspectRatio;
      end
    end;
    if OutputWidth > Printer.PageWidth then
    begin
      OutputWidth := Printer.PageWidth;
      OutputHeight := OutputWidth / AspectRatio;
    end;
    if OutputHeight > Printer.PageHeight then
    begin
      OutputHeight := Printer.PageHeight;
      OutputWidth := OutputHeight * AspectRatio;
    end;
    Printer.Canvas.StretchDraw(Rect(0,0,
      Trunc(OutputWidth), Trunc(OutputHeight)),
      Image1.Picture.Graphic);
  finally
    Printer.EndDoc;
  end;
end;

procedure TForm1.PrinterSetup1Click(Sender: TObject);
begin
  PrinterSetupDialog1.Execute;
end;

procedure TForm1.Exit1Click(Sender: TObject);
begin
  Close;
end;

end.
Martin
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